What about OpenCL support for SLI or CrossfireX interconnec?

Hi. Being new to OpenCL I hope that this question is not too elementary. I have been an electronics engineer for over 25 years and now I do a fair amount of image/video processing. I am putting together a new computer for my research, looking at both ATI and Nvidia graphics cards.

My question is, how much, if any, support is there in OpenCL for the operation of more than one graphics card that is connected as two or more cards would be by the Scalable link Interface (SLI). Other than the PCIx16 interface there is a connector on the top of the cards that is used to transfer data between them without overloading the PCI interface. Does OpenCL take this into consideration of support this?

The same question holds true for ATI CrossfireX cards. Is use of the cable interconnect interface between the cards supported by OpenCL?

I have done a lot of searching for information but I have not found any information that would be non propriatory concerning the use of these interconnects, so I am not all that optimistic that OpenCl would support either one.

The answer will have an effect upon which motherboard/graphics card I intend to purchase, at the risk of going against the whole concept of OpenCl by purchasing “targeted” hardware.

Thank You

As I see this, each Chip is interpreted as one device, regardless of intercard connection. With my 9800 GX2 each of both chips are represented as one device.
Even in SLI mode (gaming), each chip does render by his own a part of the resulting image or each render one image, and this is just connected on one card for the display.

If you use different manufactor, you’ll get different platforms. This make it just a little more complex to let all devices handle the same kernel (need to be compiled for each platform).

I test also with ATI and NVidia, just to see, how the GPU’s and CPU are used (learning OpenCL). Best would be to build up a good System (Mainboard, CPU, Memory, Power !!), and start with low budget GPU’s of each manufactor to see how they work, and later switch to high performans GPU’s you prefer. And a gfx card for running the desktop (debugging stuff) helps, when you use only one computer. My 2 cents.